Acute Oral Pain Intensity and Pain Threshold Assessed by Intensity Matching to Pain Induced by Electrical Stimuli

Aims: To investigate a recently developed pain-intensity matching device (Painmatcher) in terms of reproducibility, pain intensity, and unpleasantness experienced by healthy individuals upon pain threshold assessment, as well as differences in pain threshold between genders and between healthy individuals and patients with acute oral pain, and the relation between pain-intensity assessments by the Painmatcher and a visual analog scale (VAS) in the patients. Methods: Forty healthy individuals and 28 patients with acute oral pain participated. The Painmatcher produces an eventually noxious stimulus by increasing electrical impulses between 2 fingers. Pain thresholds were assessed twice in the healthy individuals and the provoked pain intensity and unpleasantness were recorded on a VAS. In the patients, pain threshold and ongoing pain were assessed with the Painmatcher and the ongoing pain was recorded on a VAS. Results: Painmatcher scores for the 2 pain threshold assessments were equally correlated in the healthy individuals and patients. VAS scores for ongoing pain and pain caused by the Painmatcher when the ongoing pain intensity was assessed were positively correlated. In the healthy individuals, the degree of unpleasantness was higher than the pain intensity at the pain threshold. The patients had a lower pain threshold than the healthy individuals. Conclusion: This study indicates that patients with acute oral pain have lower Painmatcher pain thresholds than healthy individuals, suggesting a general decrease in nociceptive thresholds in these patients. The Painmatcher seems to be as valid as a VAS for acute oral pain assessment. The Painmatcher pain threshold is highly reproducible but associated with unpleasantness. Keywords: facial pain, pain, pain measurement, pain threshold, visual analog scale